Lateral flow assay devices have been found to be a very convenient choice of device for many applications, especially in point-of-care diagnostics. Several different types of lateral flow assay devices are known in the art. Most lateral flow assay devices are made from a paper based or nitrocellulose based material to construct the device. More recently, fabric based lateral flow assay devices have garnered greater attention. For example, WO2009/121043 describes a cotton based lateral flow assay device. Reches et al (Reches et al, Applied Materials and Interfaces (2010), Vol. 2 No. 6, pp. 1722-1728) describe lateral flow assay devices based on cotton. In that report, the authors have attempted using the following materials as choice for lateral flow assay devices: nitrocellulose, cotton, polyester, nylon, natural silk, hemp, wool, acrylic fiber, a 50/50 blend of acrylic and cotton, and have categorically stated that the possible choices of material for a lateral flow assay device would be cotton, nylon and polyester, with cotton being the best and only choice for further studies.
WO2012/004635 and WO2012/004636 however describe the successful use of natural silk and appropriately treated silk as starting material for lateral flow assay devices.
This opens up the possibility for woven silk fibers to be used for such practical applications. Silk comprises a polypeptide chain obtained from natural sources and has been found to be biocompatible, and further comprises functional groups for any further modifications.
There is a need to develop the silk based lateral flow assay devices with a view to render it useful in a variety of test conditions for several different diagnostics testing situations.